Atomic Quadrupole Moment Measurement Using Dynamic Decoupling

TL;DR

This paper introduces a dynamic decoupling technique to precisely measure small quadrupole shifts in quantum systems, significantly improving the accuracy of electric quadrupole moment measurements in strontium ions.

Contribution

The paper presents a novel dynamic decoupling method to distinguish small quadrupole shifts from noise, enabling more accurate measurements of atomic quadrupole moments.

Findings

Measured the $4D_{5/2}$ quadrupole moment in $^{88}Sr^{+}$ with tenfold improved uncertainty.

Demonstrated the method's effectiveness in mitigating magnetic field noise.

Provided data that supports advanced quantum calculations.

Abstract

We present a method that uses dynamic decoupling of a multi-level quantum probe to distinguish small frequency shifts that depend on $m^2_{j}$, where $m^2_{j}$ is the angular momentum of level $\left|j\right\rangle$ along the quantization axis, from large noisy shifts that are linear in $m_{j}$, such as those due to magnetic field noise. Using this method we measured the electric quadrupole moment of the $4D_{\frac{5}{2}}$ level in $^{88}Sr^{+}$ to be $2.973^{+0.026}_{-0.033}\, ea_{0}^{2}$. Our measurement improves the uncertainty of this value by an order of magnitude and thus helps mitigate an important systematic uncertainty in $^{88}Sr^{+}$ based optical atomic clocks and verifies complicated many-body quantum calculations.